1. Field of the Invention
The present invention relates to a tube truncation apparatus and method.
2. Description of Background and Relevant Materials
It is known to truncate tubes by means of knives which penetrate through the thickness of the tube while the tube is rotated.
To truncate certain tubes and more particularly tubes made of a material which is only slightly rigid, such as tubes made of cardboard, it is necessary to position a counterpart within the interior of the tube on which the knife terminates its cut.
Until now, the counterpart was mechanically connected by means disposed within the tube so as to assure its fixed positioning or to allow for its longitudinal displacement.
Truncators adapted to cut unitary tubes into a plurality of truncated portions are in effect provided with knives and a longitudinally fixed counterpart, the longitudinal counterpart being fitted on a fixed mandrel on which the tube is fitted.
Conversely, in truncation apparatus for truncating a continuously formed tube, such as a spiraler for cardboard tube for example, it is necessary that the one or more knives and the counterpart follow longitudinally in a synchronous manner the tube in the course of manufacture, at the moment of cut. The knives and the counterpart are then brought back to the initial position after each truncation by a means passing through the winding mandrel of the spiraler.
It is clear that the mechanical connection of the counterpart is a handicap which prevents certain applications in particular.
For a truncator of unitary tubes, for example, the manner in which tubes were supplied until now necessarily occured on the same side as the discharge of the truncated portions because access to one side is forbidden by the linkage of the counterpart, and which would interfere with or prevent continuous supply.
In the truncation apparatus of a continuously manufactured tube it is not always possible to pierce or utilize the interior of the rolling mandrel when, for example, the diameters are too small or when the interior of the mandrel is already utilized for other purposes (heating core, cooling core, etc.) or further when the mandrel must be solid to better resist stresses.